So how do I tell cpanm (or anything else) to use either /usr/include or /usr/pkg/include but not both?

I don't think you can exclude paths, only prioritize, see export http://gcc.gnu.org/onlinedocs/gcc/Environment-Variables.html#index-CPATH-2378CPATH=...

In reply to Re: installing module but both /usr/include and /usr/pkg/include used by Anonymous Monk
in thread installing module but both /usr/include and /usr/pkg/include used by sachss

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